Boat electrolysis and static eliminator



y 1968 s. GOLDBERG E AL 3,335,254

BOAT ELECTROLYSIS AND STATIC ELIMINATOR Filed OCT 14, 1966 \Mmflm W UT u A WWW 6 W m% um Y B Fig.

United States Patent 3,385,254 BOAT ELECTROLYSIS AND STATIC ELIMINATOR Sidney Goldberg, 527 Beach 72nd St., and Albert Leitman,

533 Beach 66th St., both of Far Rockaway, N.Y.

Filed Oct. 14, 1966, Ser. No. 586,716 5 Claims. (Ci. 115.5)

This invention relates to a novel and useful method of eliminating electrolysis and electrostatic charge. More specifically, it is an apparatus adapted to eliminate corrosion of the various metallic parts of a boat in contact with water, whether inside or outside the hull, caused by electro-chemical action.

By placing two dissimilar metals used in the construction of a boat in water an electrical potential develops therebetween similar to that of a battery. In salt water the condition is more pronounced. In order to have the current flow between the metallic parts, there must be complete circuit. The rate at which the current will flow is determined by the voltage between the two metals and the resistance of the circuit. Since there is a leakage path inside the boat, due to the presence of water in and on the planks of the hull, current will flow.

One of the metals will be more positive and consequently more active than the other. At the terminal consisting of the more active metal oxidation will take place. This will be the anode which produces ions. These ions will move away and be lost to the anode. As this process continues the anode will be eaten away. The less active metal is known as the cathode. The ions will flow towards the cathode and collect thereon. This process is called electrolysis and results when the electric energy is thus used to produce chemical change.

To eliminate the electrolysis the voltage between the two metals must be eliminated. This can be accomplished by grounding all the metallic objects, both inside and outside the hull, to a common ground. This can be done very simply to all stationary objects. However, a shaft, which is rotating, presents a more difficult problem. It requires a much better electrical connection than is provided through the shaft coupling or the transmission and engine.

The electrolysis problem with which this invention is most concerned is the corrosion of the shaft and propeller which remain unprotected when using all conventional grounding, as well as the protection of other metals when the shaft and propeller become the cathode.

This invention, at the same time, will eliminate any build-up of static electricity between the rotating shaft of the boat and the associated journal.

Two bearing surfaces insulated from each other, one moving and the other stationary, will produce an electrostatic charge across the insulating material. In the case of the boat and engine one surface is the drive shaft and the other is the bearing of the transmission which is connected to the engine, separated by a film of oil acting as the dielectric insulation between these surfaces. If the electrostatic charge is allowed to build up to a sutficiently large voltage it will break down the dielectric quality of the oil separating the bearing surfaces or if a lower resistance path exists it will discharge through this path. This discharge through either path will be in the form of a spark. This discharge will be heard in the radio as static and visible on indicating eelctronic equipment as interference. The interference varies directly as the speed of rotation of the shaft. When the shaft rotates rapidly it can render the electronic equipment useless. The aim of the present invention is to prevent this charge from buildim up a voltage high enough to discharge as a spark and causing interference. Depending on the resistance of the path the voltage will build up higher for a high resistance path and will not build up as high for a lower resistance path. By providing a good electrical connection between shaft and bearings we have a very low resistance path. This low resistance path will prevent the charge from building up a voltage sufficiently large to discharge across an insulated path.

The static eliminator of the instant invention includes a base adapted to be supported within the hull of a boat adjacent to a propeller shaft of the boat journalled through the hull of the boat. A pair of support arms have one of the corresponding end portions pivotally supported from the base and the other end portion of the arms diverge toward and terminate on opposite sides of the propeller shaft. The ends of the arms remote from the base are provided with opposing brush elements and the free ends of the arms are yicldingly urged together so as to urge the brush elements in contact with the rotatable shaft. Common ground means is also provided within the hull and each of the brush elements is electrically connected to the common ground. Of course, all other metallic portions of the boat, whether inside or outside of the hull, are connected together by the most direct and shortest path. This direct connection of all metallic parts puts all the metallic parts so connected at zero potential with respect to each other and is known as common ground.

The main object of this invention is to provide a means for electrically connecting a rotatable boat propeller shaft directly to all other metallic parts of the boat hull with a lower resistance connection so as to eliminate the potential difference between all metallic parts of the boat.

Another object of this invention is to provide a device in accordance with the immediately proceding object constructed in a manner whereby it may be readily installed in substantially all boat hulls having propeller shafts journalled therethrough.

And another object of this invention is to prevent the electrostatic charge build-up between a rotating shaft and the journal associated with this shaft. If this charge is allowed to build up sufficiently to discharge across the film of oil separating the shaft and its associated journal, there will be noise in the radio and interference in other electronic receiving instruments. In boats with a high resistance path between the shaft and the journal there is the danger of an explosion due to this discharge.

Still another object of this invention is to provide an apparatus in accordance with the preceding objects which will be of simple construction, conform to conventional forms of manufacture, and be automatic in operation so as to provide a device that will be long lasting, economically feasible and trouble-free in opera-tion. This device give constant and continuous protection under all conditions that will be encountered.

These together with other objects and advantages which will be subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a fragmentary side elevation view of a boat hull modified in accordance with the present invention and with portions of the hull being broken away and illustrated in vertical section to more clearly illustrate the association with various parts of the invention with the boat hull;

FIGURE 2 is a fragmentary top plan view of the portion of the boat hull from which the electrical current conducting brush means of the instant invention are supported and illustrating the manner in which the brush elements are disposed in frictional engagement with opposite side portions of the propeller shaft of the boat;

FIGURE 3 is an enlarged transverse vertical sectional view taken substantially upon a plane disposed rearwardly of the electrical current conducting brush means of the instant invention and illustrating the manner in which the support for the brush means is secured to the boat hull, portions of the support and brush means being broken away and also illustrated in vertical section; and

FIGURE 4 is a fragmentary longitudinal sectional view taken substantially upon a plane indicated by section line 44 of FIGURE 3.

Referring now more specifically to the drawings the numeral generally designates a boat hull including a bottom 12 through which a rotatable propeller shaft 14 is journalled. The hull 10 includes a rudder post 16 which is journalled through a stuffing box 15 located at the rear portion of the bottom 12 and has a rudder member 18 mounted on its lower end. The upper end of the post 16 projects upwardly journalled through the bottom 12 and has a terminal post 22 fastened directly to the post 16. The rudder post 16 and the rudder member 18 and terminal post 22 are constructed of metallic material. A wire 21 has one end portion connected to the terminal post 22 and the other end portion is connected to one of four bolts 27 holding rudder stufiing box 15 to bottom 12, one end of a wire 24 being connected to the same bolt 27.

The hull 10 also includes 2. depending metallic strut 26 which rotatably journals the rear end portion of the propeller shaft 14 having a propeller 26 thereon exteriorly of the hull 10 and the strut 26 is held in place by four bolts 28. Connected to one of these bolts 28 is the other end of a wire 24. Also connected to this same bolt is one end of a wire 30.

The next most important metallic underwater part is the shaft-log 19 through which shaft 14 is journalled to extend exteriorly of the hull 10. Projecting upwardly from the shaft-log 19 is terminal post 19 also made of metallic material. The other ends of wire 30 is connected to terminal post 19 and also connected to terminal post 19' is one end of a wire 58.

One end of a wire 62 is also connected to terminal post 19 located on shaft-log 19 and the other end of wire 6-2 is connected to the engine (not shown) of the boat in a similar manner. In addition, by the most direct and shortest path, all other exterior and interior metallic bodies and equipment disposed below and above the waterline may be similarly grounded to the terminal post 19.

One of the most important of these bodies so connected is generally referred to by the numeral 32, and comprises the electrolysis and static eliminator of the instant invention which is generally referred to by the reference numeral 32 and includes a mount or base 34 which is secured to the bottom 12 in any convenient manner such as fasteners 36. The base 34 has a brush assembly generally referred to by reference numeral 38 secured thereto in any convenient manner such as by fasteners 40 secured through the base 42 of the assembly 38 and secured in base 34. The base 42 includes a pair of upwardly projecting and apertured ears 44 having a pivot pin 46 secured therebetween and corresponding ends of a pair of arms 48 are oscillatably supported from the pivot pin 46 with the other ends of the pair of arms 48 diverging upwardly toward the propeller shaft 14 and terminating on opposite sides of the latter. The arms are constructed of dielectric material and each has a brush member or element 50 secured thereto in any convenient manner such as by a removable fastener 52. The brush element 50 is disposed in sliding contact with shaft 14 and a pair of conductors 54 are connected between fasteners 52 and a ground post 56 carried by the base 42. In addition, the wire 58 has the end thereof remote from the terminal post 19' electrically connected to the ground post 56. The wires 24, 21, 30, 58, and 62 are all electrically connected together by the terminal post 13 which therefore defines a common ground 60, any part of the above mentioned wires constituting the common ground and connection can be made to any portion of the same and is not to be limited to the terminal post 19".

A leaf spring 64 has its opposite ends embedded in the free end portions of the arms 48 and serves to yieldingly urge the free ends of the arms 48 toward each other and therefore the brush elements 50 into contact with the shaft 14.

In operation, the brush elements 50 are maintained in sliding engagement with the shaft 14 by means of the spring 64, this permits the shaft 14 to rotate freely in either direction without binding on brushes 50 and therefore any static electricity having a tendency to build-up on the shaft 14 due to rotation and the presence of journal called shaft-log 19 is immediately conducted to the common ground 60. Further, any corrosion current having a tendency to flow between the rudder post 16, the rudder member 18, the strut 26, the shaft-log 19, the propeller 26' and the shaft 14 through the water before proper grounding to the common ground 60 will be eliminated.

By grounding all metallic bodies to common ground 60 all voltage differences between these bodies is eliminated, with all metallic parts of the boat at the same potential there can be no corrosion current flow through the water. In this manner corrosion of the rudder post 16, the rudder member 18, the strut 26, the shaft-log 19, the propeller 26 and the portions of the shaft 14 disposed in contact with the water by electrolysis will be eliminated.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

We claim:

1. In combination with a boat hull of the type including a propeller shaft journalled therethrough, a support mounted in said hull adjacent a portion of said shaft disposed within said hull, electrical current conducting brush means movably supported from said support for movement of a portion thereof generally radially of said shaft and with said portion of said brush means engaged with said shaft, means biasing said brush means toward said shaft, 3. common electrical ground in said boat, means electrically connecting said brush means and said common ground, said common ground being adapted to have other metallic portions of said hull disposed for contact by water upon which said hull is floated also electrically connected thereto, said brush means including a pair of arms pivotally supported at one pair of corresponding ends from said support for oscillation about an axis generally paralleling said shaft, said arms being divergent toward the other pair of corresponding ends thereof and toward said shaft with said other pair of ends disposed on opposite side portions of said shaft and including opposing brush elements engaged with said shaft.

2. The combination of claim 1 wherein said means biasing said brush means toward said shaft includes spring means operatively connected between said arms yieldingly urging said other pair of ends thereof toward each other.

3. In combination with a boat hull of the type including a propeller shaft journalled therethrough, a support mounted in said hull adjacent a portion of said shaft disposed within said hull, electrical current conducting brush means movably supported from said support for movement of a portion thereof generally radially of said shaft and with said portion of said brush means engaged with said shaft, means biasing said brush means toward said shaft, a common electrical ground in said boat, means electrically connecting said brush means and said common ground, said common ground being adapted to have other metallic portions of said hull disposed for contact by water upon which said hull is floated also electrically connected thereto, said brush means including a pair of arms pivotally supported at one pair of corresponding ends from said support for oscillation about an axis generally paralleling said shaft, said arms being divergent toward the other pair of corresponding ends thereof and toward said shaft with said other pair of ends disposed on opposite side portions of said shaft and including opposing brush elements engaged with said shaft, said brush elements being removably supported from said other pair of end portions of said arms.

4. In combination with a boat hull of the type including a propeller shaft journalled therethrough, a support mounted in said hull adjacent a portion of said shaft disposed within said hull, electrical current conducting brush means movably supported from said support for movement of a portion thereof generally radially of said shaft and with said portion of said brush means engaged with said shaft, means biasing said brush means toward said shaft, a common electrical ground in said *boat, means electrically connecting said brush means and said common ground, said common ground being adapted to have other metallic portions of said hull disposed for contact by water upon which said hull is floated also electrically connected thereto, said hull including metallic rudder means, propeller shaft journalling means and engine means, and means electrically connecting said shaft journalled means, said rudder means, and said engine means with said common ground, said brush means including a pair of arms pivotally supported at one pair of corresponding ends from said support for oscillation about an axis generally paralleling said shaft, said arms being divergent toward the other pair of corresponding ends thereof and toward said shaft with said other pair of ends disposed on opposite side portions of said shaft and including opposing brush elements engaged with said shaft.

5. The combination of claim 4 wherein said means biasing said brush means toward said shaft includes spring means operatively connected between said arms yieldingly urging said other pair of ends thereof toward each other.

References Cited UNITED STATES PATENTS 3,022,234 2/ 1962 Anderson 204-196 XR 3,049,479 8/1962 Preiser et al 204-196 XR 3,169,504 2/1965 Gruber .5

OTHER REFERENCES Parker, M. E.: Pipe Line Corrosion and Cathodic Protection, Gulf Publishing Co., Houston, Texas, 1954, TA 46-2, P 3 (pp. 68 and 69 relied upon).

ANDREW H. FARRELL, Primary Examiner. 

1. IN COMBINATION WITH A BOAT HULL OF THE TYPE INCLUDING A PROPELLER SHAFT JOURNALLED THERETHROUGH, A SUPPORT MOUNTED IN SAID HULL ADJACENT A PORTION OF SAID SHAFT DISPOSED WITHIN SAID HULL, ELECTRICAL CURRENT CONDUCTING BRUSH MEANS MOVABLY SUPPORTED FROM SAID SUPPORT FOR MOVEMENT OF A PORTION THEREOF GENERALLY RADIALLY OF SAID SHAFT AND WITH SAID PORTION OF SAID BRUSH MEANS ENGAGED WITH SAID SHAFT, MEANS BIASING SAID BRUSH MEANS TOWARD SAID SHAFT, A COMMON ELECTRICAL GROUND IN SAID BOAT, MEANS ELECTRICALLY CONNECTING SAID BRUSH MEANS AND SAID COMMON GROUND, SAID COMMON GROUND BEING ADAPTED TO HAVE OTHER METALLIC PORTIONS OF SAID HULL DISPOSED FOR CONTACT BY WATER UPON WHICH SAID HULL IS FLOATED ALSO ELECTRICALLY CONNECTED THERETO, SAID BRUSH MEANS INCLUDING A PAIR OF ARMS PIVOTALLY SUPPORTED AT ONE PAIR OF CORRESPONDING ENDS FROM SAID SUPPORT FOR OSCILLATION ABOUT AN AXIS GENERALLY PARALLELING SAID SHAFT, SAID ARMS BEING DIVERGENT TOWARD THE OTHER PAIR OF CORRESPONDING ENDS THEREOF AND TOWARD SAID SHAFT WITH SAID OTHER PAIR OF ENDS DISPOSED ON OPPOSITE SIDE PORTIONS OF SAID SHAFT AND INCLUDING OPPOSING BRUSH ELEMENTS ENGAGED WITH SAID SHAFT. 